Max Age

This parameter controls how long cached information is used after a
file has been cached. An entry older than the maximum age is replaced by a
new entry for the same file.

If your web site’s content changes infrequently, increase this
value for improved performance. Set the maximum age by entering or changing
the value in the Maximum Age field of the File Cache Configuration page in
the web-based Admin Console for the HTTP server node and selecting the File
Caching Tab.

Set the maximum age based on whether the content is updated (existing
files are modified) on a regular schedule or not. For example, if content
is updated four times a day at regular intervals, you could set the maximum
age to 21600 seconds (6 hours). Otherwise, consider setting the maximum age
to the longest time you are willing to serve the previous version of a content
file after the file has been modified.